How can I reduce duplication in these Bash installation functions?
Asked by
MellowCedar42
I have several Bash functions that install Docker, Docker Compose, Git, and jq. Each function repeats argument-count checks, empty-value validation, boolean validation, debug logging, and error handling. The package installers are nearly identical, while Docker and Docker Compose need additional steps such as modifying groups, enabling a service, downloading a binary, and setting permissions. Is there a cleaner way to share the common validation and installation logic without making the code harder to read or maintain?
Answers
The package-install functions are the best candidates for consolidation because they all run the same package-manager command. Docker Compose and Docker should remain separate since they perform different operations after installation. Also be cautious with `newgrp`: it starts a new shell rather than simply refreshing the current process's group membership, so it may not behave as intended inside a function or script. Usually the user needs to log in again, or a new process must be started with the updated group list. Keeping the functions explicit is preferable to making a very compact helper that hides those differences.
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The repetition is not automatically a problem—these functions are explicit and fairly easy to follow. Before refactoring, decide what you are actually trying to improve. A small helper for the repeated package-install operation would make sense, while keeping the Docker-specific steps separate. For example, pass the package name and the command used to report its installed version into a generic installer. The validation itself could also be consolidated into one helper that checks the argument count, required values, and debug flag in one place.
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MellowCedar42: That makes sense. I was mainly concerned about maintaining the same validation and error-handling pattern in every function, so centralizing only those genuinely shared parts seems safer than forcing every installer into one abstraction.